Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for HD 189733: 05-23 (100), 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100) — by astronomy; check the weather when the night is within four days.

2047-05-02astronomy score per night — click a bar for that night2047-05-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-02 Thu	75	—	unknown	01:40–04:30 (good, 2.83 h)	71.2° 06:40	6.31	48%	139.7°
2047-05-03 Fri	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.2° 06:35	6.25	58%	138.7°
2047-05-04 Sat	74	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.19	69%	134.1°
2047-05-05 Sun	75	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.14	79%	126.7°
2047-05-06 Mon	73	—	unknown	01:35–04:20 (good, 2.75 h)	71.2° 06:25	6.08	88%	117.2°
2047-05-07 Tue	61	—	unknown	01:35–04:20 (good, 2.75 h)	71.2° 06:20	6.02	95%	106.5°
2047-05-08 Wed	52	—	unknown	01:40–04:20 (good, 2.67 h)	71.1° 06:15	5.97	99%	95.0°
2047-05-09 Thu	44	—	unknown	02:20–04:15 (good, 1.92 h)	71.1° 06:10	5.91	100%	83.4°
2047-05-10 Fri	38	—	unknown	03:00–04:15 (good, 1.25 h)	71.1° 06:10	5.85	98%	72.1°
2047-05-11 Sat	35	—	unknown	03:30–04:15 (good, 0.75 h)	71.2° 06:05	5.8	93%	61.6°
2047-05-12 Sun	34	—	unknown	03:45–04:10 (good, 0.42 h)	71.2° 06:00	5.74	86%	52.5°
2047-05-13 Mon	37	—	unknown	03:00–04:10 (good, 1.17 h)	71.1° 05:55	5.69	78%	45.4°
2047-05-14 Tue	54	—	unknown	00:50–04:10 (good, 3.33 h)	71.1° 05:55	5.64	68%	41.1°
2047-05-15 Wed	62	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:50	5.58	58%	40.2°
2047-05-16 Thu	71	—	unknown	00:45–04:05 (good, 3.33 h)	71.2° 05:45	5.53	48%	42.7°
2047-05-17 Fri	80	—	unknown	00:40–04:05 (good, 3.42 h)	71.2° 05:40	5.48	38%	47.6°
2047-05-18 Sat	86	—	unknown	00:35–04:05 (good, 3.5 h)	71.1° 05:35	5.42	29%	54.3°
2047-05-19 Sun	90	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:35	5.37	21%	62.1°
2047-05-20 Mon	95	—	unknown	00:30–04:00 (good, 3.5 h)	71.2° 05:30	5.32	14%	70.4°
2047-05-21 Tue	98	—	unknown	00:25–04:00 (good, 3.58 h)	71.2° 05:25	5.27	8%	79.2°
2047-05-22 Wed	98	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.23	4%	88.2°
2047-05-23 Thu	100	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.18	1%	97.3°
2047-05-24 Fri	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:15	5.13	0%	106.3°
2047-05-25 Sat	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.2° 05:10	5.09	1%	115.1°
2047-05-26 Sun	100	—	unknown	00:05–03:50 (good, 3.75 h)	71.2° 05:05	5.04	4%	123.4°
2047-05-27 Mon	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	5.0	9%	130.7°
2047-05-28 Tue	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.96	16%	136.4°
2047-05-29 Wed	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.91	24%	139.6°
2047-05-30 Thu	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.2° 04:50	4.87	33%	139.5°
2047-05-31 Fri	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.2° 04:45	4.84	44%	135.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-02&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.